gameplay and slam dunk school

this is my first post here, good day to all

i'm having trouble playing this game on PC - it starts fine but after a few minutes into the game it starts going in slow motion and gets really choppy. i've found this question being asked in the forum but all of them are for nVidia graphics cards and mine is integrated. this is strange because i've been playing this game for over a year with no problems and about two weeks ago it pretty much became unplayable.

i also haven't found anywhere on how to do different types of dunks with a PC keyboard. i've only managed to do a 360 halfway and missing the dunk.
i've gotten quite a bit of practice with the alley oops but the finishes are always really dull and i get low points on the slam dunk contest. if anyone knows if this is possible on a PC i would appreciate your help.

here are my system specs:
Dell Inspiron 6400
1 GB Ram
Intel Core Duo t2300 @ 1.66Ghz
Intel(R) 945GM Express Chipset Family
Chip Type: Intel Calistoga Graphics Controller 224Mb
Driver Date: 12/13/2005
Windows XP Home

i tried system restore and getting update drivers but nothing changed

thanks in advance